[PING^2] [PATCH] RISC-V: fix FRM register display mask value

[Hugues de Lassus]

On Wed, Aug 3, 2022 at 11:45 AM Hugues de Lassus <hugues.delassus@sifive.com>
wrote:

> Ping.
>
> On Mon, Jul 11, 2022 at 10:58 AM Hugues de Lassus <
> hugues.delassus@sifive.com> wrote:
>
>> The FRM register is 3-bit long, but the top-most bit was masked off for
>> display, resulting in incorrectly displayed values and format strings
>> when FRM >= 4.
>>
>> Tested on riscv64-unknown-linux-gnu target, with FPU support.
>> ---
>>  gdb/riscv-tdep.c                 | 2 +-
>>  gdb/testsuite/gdb.base/float.exp | 4 +++-
>>  2 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/gdb/riscv-tdep.c b/gdb/riscv-tdep.c
>> index 69f2123dcdb..a3afab3b998 100644
>> --- a/gdb/riscv-tdep.c
>> +++ b/gdb/riscv-tdep.c
>> @@ -1185,7 +1185,7 @@ riscv_print_one_register_info (struct gdbarch
>> *gdbarch,
>>                       "dynamic rounding mode",
>>                     };
>>                   int frm = ((regnum == RISCV_CSR_FCSR_REGNUM)
>> -                            ? (d >> 5) : d) & 0x3;
>> +                            ? (d >> 5) : d) & 0x7;
>>
>>                   gdb_printf (file, "%sFRM:%i [%s]",
>>                               (regnum == RISCV_CSR_FCSR_REGNUM
>> diff --git a/gdb/testsuite/gdb.base/float.exp
>> b/gdb/testsuite/gdb.base/float.exp
>> index 62e8346928b..10c0692a976 100644
>> --- a/gdb/testsuite/gdb.base/float.exp
>> +++ b/gdb/testsuite/gdb.base/float.exp
>> @@ -112,14 +112,16 @@ if { [is_aarch64_target] } then {
>>      gdb_test "info float" "f0.*f1.*f31.*d0.*d30.*" "info float"
>>  } elseif [istarget "riscv*-*-*"] then {
>>      # RISC-V may or may not have an FPU
>> +    send_gdb "set \$frm = 7\n"
>>      gdb_test_multiple "info float" "info float" {
>> -       -re "ft0.*ft1.*ft11.*fflags.*frm.*fcsr.*$gdb_prompt $" {
>> +       -re "ft0.*ft1.*ft11.*fflags.*frm.*0x7.*FRM:7.*fcsr.*$gdb_prompt
>> $" {
>>               pass "info float (with FPU)"
>>           }
>>         -re "No floating.point info available for this
>> processor.*$gdb_prompt $" {
>>               pass "info float (without FPU)"
>>         }
>>      }
>> +    send_gdb "set \$frm = 0\n"
>>  } else {
>>      gdb_test "info float" "No floating.point info available for this
>> processor." "info float (unknown target)"
>>  }
>> --
>> 2.35.1
>>
>>